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International Standardization for QMS

The work of ISO TC 112 towards international standards for specifications and calibration of quadrupole mass spectrometers Karl Jousten, PTB, Berlin. 1. Introduction: The procedure of standardization 2. What we do and do not intend with QMS standardization 3. Content of the new ISO 14291

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International Standardization for QMS

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  1. The work of ISO TC 112 towards international standards for specifications and calibration of quadrupole mass spectrometers Karl Jousten, PTB, Berlin 1. Introduction: The procedure of standardization 2. What we do and do not intend with QMS standardization 3. Content of the new ISO 14291 4. Future work International StandardizationforQMS 1

  2. Introduction ISO Technical committee 112 Vacuum technology Chair: GER, F. Justen China, France, Germany, Italy, Japan, Korea, Russia, Spain, Switzerland, UK, USA plus 17 observers Secretary TC 112: DIN VDMA, Frankfurt WG 1 Vacuum pumps Chair: UK, St. Omrod WG 3 Vacuum hardware Chair: J, M. Hirata WG 2 Vacuum instrumentation Chair: GER, K. Jousten International StandardizationforQMS 2

  3. The procedure of standardization New work item proposal WD (working draft) CD (committee draft) 2 – 4 years DIS (Draft international standard) FDIS (Final draft international standard) Technical Specification International Standard International StandardizationforQMS 3

  4. Standardization vacuum metrology WG 2 Vacuum instrumentation • Strategy: Makethedisseminationofthepressurescale in vacuummore robust andmoreaccurateby: • Establishingthephysicsandengineeringofcomparisonstandards • Specifying all parametersneededtocalibrateanduse a vacuumgaugeand a QMS: • definethenecessaryphysicalquantitiesfortheinstruments, • letthemanufacturersspecify all importantparametersfor a calibration, • definecalibrationprocedure, • giveguidelinefor measurement uncertainty International Standardization for Vacuum 4

  5. StandardizationQMS Whatwe do not intendwithstandardsfor QMS: Pretendthat a QMS canbecalibrated in all itsfeatures Make an attempttoqualify a QMS assecondarystandard Try toguidelining a userforinterpretingcomplexspectra Whatwe do intendwithstandardsfor QMS: Make different QMS for a usercomparable (whenbuying) Establish a calibrationprocedurevaluableforthoseusersinterested in accuracyand reproducibility Givetraceabilityto SI foraselected, but relevant, application Guidelinefor proper useof QMS anditslimitations International Standardization for Vacuum 5

  6. ISO/DIS 14291 Specsfor QMS ISO/DIS 14291 Vacuum gauges– Definitionsandspecificationsfor quadrupole massspectrometers Status: DIS acceptedsince 2012-01-11 after voting (100% approval). Content: Terms andDefinitions Principleof QMS Specificationsfor QMS tobeprovidedbymanufacturers Optional specificationsfor QMS tobeprovidedbymanufacturers Scope: m/z < 300, electronimpactionization International Standardization for Vacuum 6

  7. ISO/DIS 14291 Specsfor QMS Terms andDefinitions: QMS definitionkeptfrom ISO 3529/3 Additionallydefined(hardware): Sensor head, ionsource (open, closed, molecular beam), mass filter, iondetector (Faraday, SEM, discretedynode, CEM, MCP), electronic unit. International Standardization for Vacuum 7

  8. ISO/DIS 14291 Specsfor QMS Physicalparameters: Sensitivity(M* for N2): p partial pressure, p0 residual pressure (needs not tobeknown!). As AVS recommendation, but different fromsensitivityofiongauge! O*: Temperature coefficientofS Relative sensitivityfactor: *MMandatoryspec *O Optional spec in ISO 14291 International Standardization for Vacuum 8

  9. ISO/DIS 14291 Specsfor QMS Massresolution: Difference on m/zscalefor x% valleybetweenneighboredpeaksofequalheight (0.5x% heightisolatedpeak). 10% valley, 5% peakheight IUPAC goldbook, ISO 14291 (M) Alternatives: 20% valley, 10% peakheight: easiertomeasureagainstnoise (AVS recommendation) FWHM (50% peakheight), IUPAC recommendation, ISO 14291 (O) International Standardization for Vacuum 9

  10. ISO/DIS 14291 Specsfor QMS Massresolving power: Massnumberstability: Mfor He or Ar (Discussed: N2) Minimum detectable partial pressure: Mfor He, Ofor Ar (AVS : Onesigma!) Discussed: N2 Minumumdetectableconcentration: Mforoneselectedmixture, recommendedfor He, Ar orKr in air Fragmentationfactor: Oforwater, methane, nitrogen, carbonmonoxide International Standardization for Vacuum 10

  11. ISO/DIS 14291 Specsfor QMS Non-linearity: DS in a certainpressurerange Linear responserange(M): partial pressurerangewhereDS < givenvalue Stabilityofpeakheight (peakintensity): atconstant partial pressure (AVS: Drift) Intentionallywedid not (yet) define (out ofscope): tailingcontribution (toomuchofworkformanufacturers), massdiscrimination (iontransmissionvsm/z), incrementalsensitivity (sensitivityat a certainoperatingpressure/mixture) International Standardization for Vacuum 11

  12. ISO/DIS 14291 Specsfor QMS Max bake-out temperature Operating conditions Warm-up time Electronemissioncurrent Filament exchange Detectorexchange Fitting tochamber Mountingorientation Dimensions Internal volume Weightofsensorheadandelec. unit Input power Cable Software Interfaces Storage andtransportationconditions List ofmandatoryspecs (32) formanufacturers: Massrange Type ofionsource Massresolution Massnumberstability Sensitivity Linear responserange Min detectablepressure Min detectableconcentration Max operational pressure Scanning parameters Signal output (I, p) Potentials Detectorspecs Set pointsavailable International Standardization for Vacuum 12

  13. ISO/DIS 14291 Specsfor QMS List of optional specs (9) formanufacturers: Massresolution (FWHM) Sometypicalfragmentationpatterns Temperature coefficientofsensitivity QMS sensorcleaning Degassing Degassing power Photographs Inspectionrecord Outgassing rate International Standardization for Vacuum 13

  14. Standardization vacuum metrology Additional future work • Collectitemsforimprovementsfor ISO 14291 • Collectresultsfromrecentinvestigations on QMS characteristicsandcalibrationsanddrawconclusions (Underwhichconditions a QMS calibrationisuseful? Whatkindofcalibrationbringsvaluefortheuser? Whichconditionsare robust and easy toprovide?) • Draft a technicalspecificationtocalibrate QMS • Long term: Uncertaintiesassociatedwith QMS calibrationandmeasurements International Standardization for Vacuum 14

  15. Standardization vacuum metrology Discussion International Standardization for Vacuum 15

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